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Hominid Evolution & Classification. Chapter 16. Hominid Skulls. Subject A = Chimpanzee Subjects J-L = Neanderthal (70,000 to 45,000 years ago) Subject M = Cro Magnon (30,000 years ago) Subject N = Modern Man. Human Classification. Domain: EUKARYA Kingdom: ANIMALIA Phyla: CHORDATA
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Hominid Evolution & Classification Chapter 16
Hominid Skulls Subject A = Chimpanzee Subjects J-L = Neanderthal (70,000 to 45,000 years ago) Subject M = CroMagnon (30,000 years ago) Subject N = Modern Man
Human Classification Domain: EUKARYA Kingdom: ANIMALIA Phyla: CHORDATA Subphyla: VERTEBRATA Class: MAMMALIA Subclass: EUTHERIA Order: PRIMATA Suborder: ARTHROPOIDEA Family: HOMINIDAE Genus: HOMO Species: SAPIENS • Humans are members of an order of mammals: primates. • Primates first appeared about 65 million years ago. • The first primates lived in trees, and we have inherited some of their characteristics.
Characteristics of Primates • Highly diverse group with the following general features in common • Manual dexterity: an opposable first digit • Senses: • Binocular vision (eyes on the front of the face allowing for overlapping fields of vision) • Color vision (if diurnal) and black/white vision (if nocturnal) • More brain power devoted to vision than smell • Locomotion: flexible bodies that allow for easy movement • Complex brain and behaviors: problem-solving, socializing, and communicating • Reproductive rate: fewer offspring; single births
Other Primates Great Apes • Chimpanzees • Orangutans • Gorillas • Humans Female orangutan Male orangutan
Suborder: Arthropoidea Domain: EUKARYA Kingdom: ANIMALIA Phyla: CHORDATA Subphyla: VERTEBRATA Class: MAMMALIA Subclass: EUTHERIA Order: PRIMATA Suborder: ARTHROPOIDEA Family: HOMINIDAE Genus: HOMO Species: SAPIENS • Arthropodoidea: all non-monkey primates • Genetically speaking, humans are most closely related to apes. • These primates lack tails and have forelimbs longer than their hind limbs
Chromosome Analysis • We share more than 97% of our genes with chimpanzees. • Our behavior also has some similarities. • Chimpanzees make and use simple tools. • They seem to have a sense of self.
Primate Evolution Cladogram Domain: EUKARYA Kingdom: ANIMALIA Phyla: CHORDATA Subphyla: VERTEBRATA Class: MAMMALIA Subclass: EUTHERIA Order: PRIMATA Suborder: ARTHROPOIDEA Family: HOMINIDAE Genus: HOMO Species: SAPIENS
Hominid Evolution The human branch of the primate tree is only a few million years old. Apes and hominids diverged from a common ape-like ancestor between 8 and 5 million years ago.
Hominid Characteristics • Big brain with more complexity in areas responsible for reasoning • Thinner face with smaller teeth • Long thumbs and flexible wrists • Bipedal (upright walkers): • Shorter arms • Restructured pelvic and foot bones • Hole for spinal cord at the base of the skeleton rather than the back
Genus: Homo Domain: EUKARYA Kingdom: ANIMALIA Phyla: CHORDATA Subphyla: VERTEBRATA Class: MAMMALIA Subclass: EUTHERIA Order: PRIMATA Suborder: ARTHROPOIDEA Family: HOMINIDAE Genus: HOMO Species: SAPIENS • Continued structural changes: • Larger brains • Thinner faces • Smaller teeth • Significant advances: • Used tools • Hunted and gathered food • Used fire • Built shelters • Developed culture and communication
Species: sapiens • Binomial classification: use the genus and species names to refer to an organism • Homo sapiens (modern human) appeared in Ethiopia about 195,000 years ago. 200,000 years ago, many species of the Homo genus were present.
Out of Africa Hypothesis (1988) • 200,000 years ago, many species of the Homo genus were present. • 30,000 years ago, only homo sapiens remained. • WHAT HAPPENED TO THE OTHER SPECIES? • 1988 Out of Africa Hypothesis: modern humans evolved in Africa and then migrated to other parts of the world.
Out of Africa Hypothesis (1988) • In the 1990s, scientists learned about mitochondrial DNA. • Mitochondrial DNA is a smaller fragment of DNA found in the mitochondria of eukaryotes. Only 37 genes are located on human mitochondrial DNA. All of these genes are related to mitochondria function. • Mitochondrial DNA is ONLY inherited from mothers as sperm mitochondria are destroyed by the egg after fertilization. • Mitochondrial DNA changes very little over time. It takes many years for mutations to occur. • Remember molecular clocks? The more mutations…the longer the species has existed. • Scientists have studied mitochondrial DNA from humans all over the earth. They found that people in Ethiopia have the most mutations in their mitochondrial DNA. • Therefore, humans likely originated in Ethiopia from a “Mitochondrial Eve.”
Final Overview of Family HominidaeEvolution ? Australopithecusrobustus Homoergaster Australopithecusafricanus Homosapiens Australopithecusafarensis Homoneanderthalensis Millions of years ago Homoerectus Australopithecusanamensis Homohabilis Australopithecusboisei Ardipithecusramidus Ardipithecusramidus kadabba Orrorin tugenesis